A Scientific Theory of the WTC 7 Collapse

Brian

February 24, 2011 at 10:20 pm

http://www.youtube.com/watch?v=rVCDpL4Ax7I

http://www.youtube.com/watch?v=-jPzAakHPpk&playnext=1&list=PL8FA177BD5899D57B

Case closed

Brian

February 24, 2011 at 10:28 pm

http://www.youtube.com/watch?v=rVCDpL4Ax7I

http://www.youtube.com/watch?v=-jPzAakHPpk&playnext=1&list=PL8FA177BD5899D57B

Case closed.

All that remains to be investigated is who knew planes would be flown into the twin towers on 9/11 and prepared WTC 7 for demolition in advance of 9/11.

Sean

February 25, 2011 at 6:04 am

Nice posts, I agree Case closed

Greg

February 25, 2011 at 1:51 am

Jeremy, I don’t have a background in engineering, but I do in physics. But I don’t understand what you are talking about.

If there were no explosives, then the bottom of the building is crashing under the force exerted on it by the top, as there is no other force. By Newton’s third law, there is an upward force exerted on the top by the crashing bottom, which is of the same magnitude that the top exerts on the bottom to crash it (but opposite direction). So the sum of all downward forces exerted on the top is the gravity minus the force that the crashing bottom exerts on the top. That is, the net downward force acting on the top is less than gravity. So by Newton’s second law the acceleration of the top has to be less than free fall. Since it is a fact that the top was coming down with free fall, the hypotheses that there were no explosives is wrong. It is that simple.

Jeremy R. Hammond

February 25, 2011 at 2:28 am

Yes, like I said.

Greg

February 25, 2011 at 11:08 am

Oops, sorry, I meant to address my previous comment to Jeffrey, not Jeremy.
I don’t know what Jeffrey is talking about.

Jeremy R. Hammond

February 25, 2011 at 12:08 pm

Ah, that makes more sense! LOL! Gotcha.

Jeffrey Orling RA

February 25, 2011 at 1:38 pm

Sean,

There were a few bits of time where there was free fall collapse traced on a point on the roof line. In WTC 7 and also in tower 1 for perhaps a second when the top began to descend.

The rest of the collapses were significantly less than free fall and were clocked at something like 60+ mph.

One aspect of the collapse AFTER initiation is that there was a continuous roar which was the sound of the floors collapsing. There were no massive percussive explosive sounds.

Another thing to note which points to a progressive runaway floor collapse (avalanche) is the fact that most of the core remained after the floors were gone and virtually ALL the facade panels came off the building and fell outside the foot print. These two bits of evidence indicate that the floors were destroyed FIRST and then the facade peeled off and finally the core collapsed from Euler buckling.

The material seen ejected through the facade at the crush front is the air carrying light building materials and floor contents out the windows. The air HAD to be displaced as the falling mass pushed down on it and the air escaped through the glass areas which offered the least resistance. I think this makes perfect sense and attributing these ejections to hundreds of sequences of explosives on each floor at 1/10 second apart is not plausible and the probability very low.

The building was almost 97% air and the floors DID offer some resistance, but not much enough to arrest the hundreds of thousands of tons of rubble coming down.

No CD company would even consider exploding the floors over 104 floors. There is no evidence of the core columns being exploded… certainly in those from BELOW the crash zone. All those columns broke apart at their joints.

Sean there are programs which do finite element analysis and can show a progressive failure.

I invite you to become a member of the 911 Free Forums which accepts qualified scientists and engineers. Anyone can read the threads.

http://the911forum.freeforums.org

I have been doing my own research focused on the twin towers and their structure in particular. I have some slides I can share with you if you are interested… send me an email to jsandero at gee mail dot com.

In both 7 and the twins’ collapses we need to understand the initiation of what I am convinced were then gravitational collapses. The initiation took place inside behind the facade in the core area and so it virtually impossible to see it.

The best analysis of the videos to date is being done by several scientists at the 911 Free Forums. They do not support the NIST explanation for the cause of the collapses. Neither do I.

However, if one studies the structural design and notes how vulnerable they were to the floors being “disengaged” from the columns and going into a run away collapse mode, you are left with looking more narrowly to explain what kicked it all off.

I believe that the initiation was NOT as complex and massive as many would believe. Conceptually it like tipping one domino to knock down a thousand. In this case it likely wasn’t fire to tip the first domino and it wasn’t the plane strikes.

There is apparently a cognitive dissonance going on. WTC 7 whatever the cause that started it all.. was a gravitational collapse…. even at free fall for 2.25 secs and slower as the top section was crushing itself. 7 produced all dust, no slabs, lots of remain steel broken at joints, twisted and mangled. The perimeter columns came down with the collapse and everything seemed to fold into the core which went first. A giant cloud of dust spread and billowed out from the collapse.

The twins too produced the same billowing clouds, the same lack of large concrete yet too the same average time for the floors to “destruct” and left virtually all the steel broken at the joints and some mangled from the fall. The facade columns were on the skin of the building and were pushed away by the collapsing floor avalanche, and the core was “left standing” as high as floor 77 in the case of col 501. The core was left because the floors collapsed and were ripped off the column support. And the core succumbed to Euler buckling… we see most of the remaining core columns topple from instability and some of them collapse from Euler buckling.

If you look carefully this is what you see in the collapse of the twin towers. We don’t know what the initiation was. Office fires cannot produce the floor collapses and column displacement to kick off the runaway collapse.

Why the resistance to a floor collapse with a engineered initiation? There is enormous resistance to this and it NOT the official story at all. I don’t get it frankly.

Saying this was planned decades ago requires some hard evidence and I don’t see it. That sort of speculation is not helping us get to the culprits.

Jeremy R. Hammond

February 25, 2011 at 4:19 pm

“There were a few bits of time where there was free fall collapse traced on a point on the roof line. In WTC 7 … perhaps a second when the top began to descend. The rest of the collapses were significantly less than free fall….”

Absolutely false. Everything you say that follows rests upon this false premise.

Jeffrey Orling RA

February 25, 2011 at 1:44 pm

Jeremy,

A column does NOT have to be destroyed to have it offer 0 resistance. A column can be “pushed” out of the way. If you remove a guy wire, for example the structure it supports losses it bracing and it will buck or fall and it is NOT destroyed. It’s carrying capacity was been destroyed. The load path has been destroyed, but the column does not have to be.

If you drive into your garage and knock over the steel lally column the floor above will come crashing down. Under the rubble you will find the lally coiumn, probably bent.. but all there.

Jeremy R. Hammond

February 25, 2011 at 4:20 pm

Jeffrey, a column that offers zero resistance is a “destroyed” column, by definition.

The only question we’re concerned with here is HOW the columns of WTC 7 came to be destroyed.

Jeffrey Orling RA

February 25, 2011 at 1:47 pm

Greg,

As a physicist are you familiar with Euler’s formulas for slender columns and self buckling.

Perhaps you could explain to the readers how a too tall slender steel column can buckle from its own weight.

Thank you!

Sean

February 25, 2011 at 4:05 pm

Jeffrey you are completly oblivious to the evidence of eye witnesses and audio video of expolsions heard before the building fell (WTC 7). This was the removale of the core column footings…the initial failure is in the center of the building in which we see the penthouse slouch…once this slouch occured the outer columns follow the initial bow in the center and are then coming for the ride down.
Also you are oblivious to other posts where a high school teacher shows that free fall exists for 2.25 seconds so there is no resistance from columns, hence they have been sabotaged to not offer any support of any kind.
WTC 1 and 2 were exploded with charges of thermate, there is irreputible evidence of thermate at this location and when ignited it explodes, these charges can be seen coming from the columns blow as well….air does not blow clouds of grey smoke and eye witness on the 80th floor said his office exploded, the building was not falling at this point so where did that explosion come from….therefore I am concluding the columns were all attacked with thermate, that is why all the steel was destroyed so that there would be no evidence of it. You are doing exactly what NIST tried to do….you are trying to fabricate something when it does not exist, the evidence is overwhelming if you look at the posts Brian just put up you will see for yourself, all buildings were sabotaged from the get go, key individuals knew the planes were coming and rigged the buildings….try chasing that for awhile and tell me when you come upon a stumbling block look at sabotage and you will see that all falls make perfect sense.

Sean

February 25, 2011 at 7:49 pm

Jeffrey, since you are so convinced that the columns failed because they lost their supports. I will give you table loads not by my hand; but rather straight from the Handbook of steel construction (HSC) with regards to load vs effective length.
Lets take a W360 X 1086, this is an I-shaped section…360 is the width in mm and 1086 is what the beam/column weighs per m in kg…….at 8.2ft in height it can hold 42100kN or 9,464,928lbs, this is with respect to the least radius of gyration meaning the table is with respect to the strong axis, if we use the weak axis then the numbers decrease but they decrease by the same amount or at the same rate that the strong axis does….just to be clear the 8.2 feet is considered as unsupported, now from the table when I increase the UNSUPPORTED length to 52ft the load it can carry decreases to 11,800kN, this means your buckling failure is highly improbable, you see as I explained before these columns need to support hurricane conditions and fictious loads which then multiply by 5 to have a sf of at least 5, so if I do this math that means 5 x 11,800kN = 59,000kN this means the column can still support more than what it originally started with at 8.2ft considering the load of 42,100kN
I could do this all day with every column in this book and the results are the same….at what point will it buckle under it’s own weight, well just add up it’s weight per m, but this table includes the weight so these are the actual ratio’s, so for a column to buckle you need to lose more than 4 floors of bracing, which is an impossible task unless you plan it, since there were no hurricanes and no people in the building the sf of the buildings columns themselves would have been much greater than five because the five is taken after the fact with the people loads and hurricane conditions since neitheir of these existed your actual sf was in the neighbourhood of 8-10 so your column would have to be over 100ft with no lateral bracing if you get the picture now.

And yes if you induce a lateral load into the column you can reduce the carrying capacity, but as rational will tell you without live loads due to hurricane and floors fictiously loaded with people every square foot that did not exist and sf of 5 min built into the structure……one can see that without eliminating the columns without explosives you cannot fail these columns because in reality their failure capacity is almost non existent without the hurricane condition so a runaway condition cannot exist especially because eliminating bracing is hard to believe in the first place and even if you can present that scenario, they are still massively strong.
However where how and who planted the sabotage is what we need to find out. We can’t do that because when we ask Bush to explain he says nothing, hoping we can see that the speculation is so ridiculous that he doesn’t have to answer the question. This represents a guilty person on the stand much like a guy who just killed his wife, he says, that’s ridiculous..I don’t have to answer that…and who can force him to answer…pretty much nobody, the only way we have more power is if we all stand as one, we elected him therefore we are the power but we need more attention, does anybody know how to get some???

Greg

February 26, 2011 at 1:02 am

Jeffrey, clearly, a column that is too thin, can buckle under it’s own weight. But it certainly does not do so with free fall man. Not until the point when it breaks.

Greg

February 26, 2011 at 1:13 am

Jeffrey, what you need to explain to us is how it is possible for not one, but many columns, that were designed to hold the whole building, to stand straight in one moment and offer no resistance at all in the next, do this in a completely symmetric fashion, and through some 30 meters. If the columns were blown out of the way, since the building fell free through some 30 meters, all the columns at the same instance would have had to be blown out along that 30 meters. The floors also would have had to get detached from the columns at the same time, otherwise still there would be big chunks of the building that would have had to be crashed. All this in one moment.

And how do you explain the extremely symmetric way of falling?

In fact, it is clearly visible in this video
http://www.youtube.com/watch?v=cZsA3xb2kOA
at 1:50 that the removal of the columns was not perfect on the left side, and there the fall meets resistance. That is the kind of thing we would have to be seeing all over the building if it was a natural collapse.

Collapses that show similar features have been reproduced many many times in the form of controlled demolitions. I don’t think anyone can show a video of a known natural collapse of anything, let it be just a single thin column, that displays similar features to the collapse of wtc7.

Furthermore, the theory of explosives is supported by eyewitness accounts and that scientists found remainders of explosives. Moreover, while there are plenty of strong arguments why it cannot be a natural collapse, there is no argument against explosives other than “who could have put them there?”.

Jeffrey Orling RA

February 26, 2011 at 4:40 pm

You don’t have to remove 100 vertical feel of columns support all at once because it takes 2.25 seconds to fall that distance. In the first second you only have to remove 16′ of vertical support or one single set of 26′ tall columns. Let’s be clear about this.

If you HAD removed 100 feet of columns in that first second… the falling mass would take 1.25 seconds to reach the “bottom” where the columns had been destroyed.

NO YOU DON”T HAVE TO REMOVE 100 FEET OF STRUCTURE AT ONCE TO GET A FREE FALL ACCELERATION FOR THOSE 100 FEET.

The weakest part of the long span open office column free space is the floor system – NOT THE COLUMNS. Each floor system was designed to support less than 100#/ft (58# for the twin towers). The floor loads were carried on beams and then framed into girders in some cases. These loads then were attached to the side of the columns.

If the floors are overloaded past their yield strength they fail and can’t transfer the load to the columns. This COULD cause the beams, and the girders to fail and be stripped off. An attack could be focused on the grider to column connection point (beam stubs). As one connection of the floor load to a column is failed the remaining ones pick up the load. If enough of the loads are redistributed to too few girders to columns connections these remaining ones will also fail. This is how a progressive failure through a structure proceeds. In order for there to be a global failure there needs to be too few members carrying too much load. It’s really that simple.

A progressive collapse will arrest if the load redistribution does not exceed the yield strength of the members seeing increased (redistributed loads).

If you forget about the FF 2.25 seconds and move to the period AFTER that… what was happening? The undamaged structure… floors were seeing loads too great for them to support… so the bottom was crushed by the (dyanamic) loading of the descending mass. When that mass had crushed all the remaining bottom the descending mass then crushed to bottom of itself if there was enough dynamic load to do so. Some CDs fail and the top section simply supports itself, perhaps tipped a bit because the dynamic load was not enough to crush up from the bottom. As the in tact mass decreases from the crush up, there is less likelihood that the CD will complete itself.

The destruction of 7 took much longer than 6-7 seconds. It likely began with muitiple floor girder to column failures and then partial floor collapse near those columns. This led to unbraced columns buckling in the core, the collapse of the east penthouse which gutted a huge section of the center of the building right ton the ground… then more columns were left unbraced and buckled pulling in the outside the core floors above and the girders and beams supporting them including the perimeter columns inside the curtain wall.

The top did not collapse as a block and careful examination of the video shows it twisting, tipping to the east and then west, bowing of the north facade into the core and so forth as it was collapsing. It was showing INTERNAL stress and and could not be falling with no resistance, otherwise there would be nothing but the block dropping straight down. It simply does not. This is a GROSS observation not a precise one.

There were reports that the building was distorting BEFORE it fell if I recall correctly. It was being monitored and this was a sign – the distortion – that the internal structure was undergoing a progressive series of structural failures. When it reached a point of no return it (yield point) it “let go” and the failures raced through the structure very rapidly and it fell.

I do think it likely and possible that the initiation was not fire. I don’t think that fire could cause the failures we saw. But I do think that it was a PROGRESSIVE failure and not every member had to be attacked for this to occur.

So in twin towers once enough mass was made to descend on the floors, the runaway collapse of the rest of them was inevitable, unstoppable and required no additional engineered intervention.

I suspect that the open office floor design facilitates a run away floor collapse….not from a single floor perhaps, but from sufficient number of consecutive ones and that’s all it takes.

How many floor masses (load) do you think a typical WTC 1,2 or 7 floor can support without collapsing?

Jeremy R. Hammond

February 27, 2011 at 1:31 am

You don’t have to remove 100 vertical feel of columns support all at once because it takes 2.25 seconds to fall that distance. In the first second you only have to remove 16′ of vertical support or one single set of 26′ tall columns. Let’s be clear about this.

If you HAD removed 100 feet of columns in that first second… the falling mass would take 1.25 seconds to reach the “bottom” where the columns had been destroyed.

No, Jeffrey. You can’t make it fall faster than free fall by taking out longer sections of column at once. Most of your remarks seem premised upon this fallacy, so no need to address them further.

The top did not collapse as a block and careful examination of the video shows it twisting, tipping to the east and then west, bowing of the north facade into the core and so forth as it was collapsing. It was showing INTERNAL stress and and could not be falling with no resistance, otherwise there would be nothing but the block dropping straight down. It simply does not.

Jeffrey, my goodness, it collapsed “as a single unit” (NIST’s words) at an acceleration for 2.25 seconds indistinguishable from the acceleration of gravity. By definition, that means there was no resistance! It’s that simple.

Jeffrey Orling RA

February 26, 2011 at 5:46 pm

If you look at column 501 in the Spire in serveral of the videos you can determine how fast it drops “from its own weight”. It stood over 900 feet tall … up to floor 77-78 before it is seen dropping vertically from “self buckling”

There is one view in a film which was taken from the NE and you can see the water tank on the roof of 90 Duane street. It blocks most of cc 501. You can see the part of the column where it is joined to cc 601 at about 15 floors down at floor 63 or so. It stand 180′ or so above that point. You can also see it below that point for about another 15 floors.

CC501 drops in a couple of frames and with the frame rate you can gauge the speed of decent. It appears to drop out of site in a few frames and this will compute to free fall. CC501 was 26 – 36′ segments and when it self buckled… it broke apart at one of the lower column to column joints and it went “out of column”. Weighing over 900 tons in total, the top section drop rather quickly with nothing to resist it.

Study this column collapsing and you can see a column self buckling once the bracing has been removed. The S/R ratio is approaching 500 and far exceeds what such a column (segmented) can be expected to stand up and not buckle from its own weight.

Jeffrey Orling RA

February 26, 2011 at 5:51 pm

The towers fell symmetrically because the CG was inside the foot print and in the case of 7 it was destroyed in the core first and collapsed into itself. The twins’ floors collapse down and there was no moment or horizontal impulse.

Parts of the top of 2 did go outside the footprint, but the greatest force was straight down and inside the footprint.

Why would they fall over to the side?

Sean

February 26, 2011 at 5:52 pm

I am not arguing about progressive failure occuring, it obviously did. However fire will not cause this because you need multiple strategic planned failures to do so. In other words I am saying something like explosives combined with thermate weakening caused the failures. I know how strong these buildings are is basically my perspective.
Lets look at the floor load you are presenting which is 100lbs per square foot (common live load to use sometimes less sometimes more) note however this 100lbs per square ft is huge, take a floor area of 100ft x 100ft multiply that by 100 lbs/ft squared = 1,000,000Lb point load which did not exist but was built into the design multiply this by 1.5sf then figure out what the dead load of the floor is and multiply by 1.25, then multiply other possible dead loads such as partition walls book shelves etc and there will be a code requirement for this as well, I cannot right an essay here it is too long and I am giving the reader a generalization and without knowing the floor loads how they were built where the loads went to and without blueprints behind it I cannot be accurate on how many floors it would take to cause one floor to fail and neither can a computer, I just have a realization of how strong the building is especially without disaster like conditions other than the fire which is known by history to never bring down a building anywhere across the entire globe.

Investigators said from the start if we don’t stop destroying all the evidence that we would be left with nothing but computer models as a reference and guess what we are left with computer models, this is great for the culprits because they are the ones inputing the data…the data is corrupt and we caught them doing so once already, the model is only as good as the information you feed it so models cannot tell you how a failure occurs. No one connection is the same no series of bolts even one bolt will break at the same load, it all varies, therefore if one support breaks and another support holds on for a little longer then the buildings load shifts and falls to a different location unknown where it will land and in carnage these loads are shooting of in all directions due to improbabilities, no computer can analyize that because we are feeding it the numbers and we do not know.
In CD they remove the columns footing from the base once you remove the base, the loads and eccentricties relay through the buildings entire structure and folds on itself floor by floor as the weight of each floor pulls from the roof line at it’s center and you only need a small movement to start when the correct columns are removed. Again look at buildings damaged in the surrounding area’s they are still in one piece only local damage occured. This is typical of all buildings, in CD evry building will fall now you are saying this building had it’s own way to progressively fail if enough floors fell on top of each other but I believe other parts of the building would still be standing. And I am certain of it because even in eathquake hit areas building don’t completly demolish themselves, they topple and collapse but parts remain standing.

Jeffrey Orling RA

February 26, 2011 at 10:09 pm

Sean,

I agree with the garbage in equal garbage out. I also agree with those who point to NIST looking for a justification for a fire based cause and came up with a non credible scenario.

However, we do need to agree on what we saw and we do need to focus on the initiation in all three collapses.

If we can demonstrate that the initiation was engineered and not the result of fires it doesn’t even matter whether the collapse was explosive assisted or not.

I can’t emphasize enough that ALL the focus of the truth movement needs to be in the INITIATION not in the fact that the COLLAPSE looks like a CD. A CD IS a gravitational collapse with an explosive kick off.

Some try to demonstrate that there were explosives DURING the collapse and if this can be done conclusively it would be damning. I haven’t seen conclusive evidence of explosives in the collapse phase which I believe can be explained by a progressive gravitational collapse.

I would like to have ALL the attention focus on what LED to the collapse because what NIST said for 1, 2 & 7 is not believable and shows errors. Falsifying their cause/initiation does NOT mean it was an explosive controlled demolition. That needs to be PROVEN. And this IS an engineering issue.

One also needs to understand that if this was an engineered take down, the planners had to PLAN how to do it. Why can’t we? Assuming they planned it they must have had some idea of what it would look like.

We have the plans, the basic structure and I challenge the engineers in the truth movement not to simply say it HAD to be CD because X, Y & Z, but to tell use HOW to do it… precisely how it was done because that’s what THEIR engineers did. And we have the advantage that we can SEE the collapses which resulted. THESE should contain clues.

This may be a called for “speculation”, but this is hardly much different than calling construction plans – speculation that the building will stand.

But this can only be done by engineers who understand how buildings stand and how structures fail. To stay these buildings were so strong is childish.

This is an engineering problem and it can be solved. It may not produce the exact demo plan, but it will produce one that is credible and sufficiently detailed and hopefully is supported by all the observations.

Jeremy R. Hammond

February 27, 2011 at 1:40 am

Jeffrey, for WTC 7 to have collapsed as it did, columns had to have been cut. I don’t see how too go about doing that without the use of some kind of explosives/thermitic materials. If there’s another way to accomplish that I’m unfamiliar with, please let me know.

Brian

February 27, 2011 at 2:31 am

All tyranny needs to gain a foothold is for people of good conscience to remain silent. Thomas Jefferson

http://buildingwhat.org
http://www.l911t.com
http://ae911truth.org
http://pilotsfor911truth.org
http://rl911truth.org
http://firefightersfor911truth.org
http://www.informationclearinghouse.info/article23969.htm

Sean

February 27, 2011 at 4:28 am

Jeffrey, I pointed out a lot of ways why they are strong enough to stand on there own without having to write an essay on the topic; it is a generalization of why they are so strong, if you believe this to be childish so be it, you are a fool not to recognize the value behind that, because that is credible and relates to the corrupt report from NIST with regards to free fall. We need people to understand the generilzation of the strength of buildings if they are going to stand with us, they will not understand the math behind it. You have forgotten what I said last time….we have little evidence….we are left with computer simulations, we need a generalization of how strong these buildings are and then put this into the media mainstream so that your relatives mine and America will understand that buildings don’t fall down on their own……if you try to boggle our supporters with engineering you will lose.
The culprits are scared of mass attention…this is politics at play against us and them…tell the masses something they can understand an engineering report won’t win you any votes and we need votes…it seems we are winning but we need more publicity, anyone I talk to only remembers that thermate was ruled out by the media and never heard of a third building falling….so don’t rule out a generalization of how strong these buildings are…prove their potential and people will understand why it is so hard for engineers to believe that these buildings fell due to fire.

Heres another engineering fact on strength…and I bet if an engineer familiar with the as built drawings of this building can verify because I garantee it’s wrong. Nist reported that the girder broke when the connection reched a temperature that reduced that connection to 50% of it’s strength….now lets dig into this a little and I hope someone familiar with the building and the NIST report is listening

All conections by code are connected to a minimum standard of 50% of the shear capacity of a beams shear strength…now wityh beams that are longer than a stub will always fail in bending and shear strength of the beam is ridiculously strong….lets take a W460 x 89 that is 5-meters long…consider this the girder with beams framing into it the uniform load that fails this member in bending for a simply supported girder at a 5-m length is a 140kN/m….this means you would have a shear force of 352kN at each connection at the girder….the girder beam has a shear strength of 996kN designed at a minimum of 50% so it had a strength of 498kN…if it lost 50% of it’s strength it would still have 249kN of strength….sounds good for Nist except there were no live loads on that floor that brought the weight of 249kN to that connection, there were only dead loads that had safety factors as well……I believe if someone chases this you will find that that support had no where near 249kN at it’s location because this load is the maximum for that beam and engineers never design to 100% capacity usually only 80% which further reduces the numbers also engineers may pick a beam that is even stronger than wht is required for strength due to deflection and this will further reduce these numbers….if we prove NIST wrong here than what started the sequence for them will be no good thus there report would be false… but I don’t know what the beam was or what the loads are or the floor plans or the framework of the beams or whether or not the girder was a simple support so I can’t chase engineering principles, all I have is my general knowlege, trying to strip my credentials and my willingness to try to help is childish.

Good Luck Jeremy, I hope you know someone who can look into the shear capacity of that girder because I will bet on it that it takes a lot more than a 50% reduction in strength to that support caused by fire to break it because live loads are large and they didn’t exist and shear connections are stronger than they have to be by a large margin, that is why code allows engineers to design to only 50% but it’s still too strong for what it needs to do….if we prove NIST wrong again…. then they have no start point???

Jeremy R. Hammond

February 27, 2011 at 10:38 am

Well, that is why NIST came up wither their hypothesis of “thermal expansion”. It was the expanding beams that pushed the girder of its seat at Column 79. From an as-yet unpublished paper I happen to be working on:

In comments on the draft report, the Council on Tall Buildings and Urban Habitat (CTBUH), after observing that shear studs and bolt connections failed at temperatures under 200°C, stated, “The failure of shear studs is surprising, and has been modeled in a very simplistic way, which may overestimate the failure of this element. Prior studies and real fire cases have not previously identified shear stud failure as a significant possibility” – which might explain why NIST was unable to find any literature on it. A “more accurate shear stud model” might have produced a different effect, and, additionally, “It is difficult to understand why the top bolts of the girder would fail at connection to Column 79. Such failure would mean the slab had moved relative to Column 79.” This, too, was attributed to the “limited” analysis model. The Council asked, “If the primary girder had shear studs would the floor have failed?”

By NIST’s own calculations, the answer appears to be that the girder (and thus the floor) would likely not have failed even if the girder had shear studs. NIST gives the equation for calculating a change in length due to thermal expansion (δT) as being equal to the coefficient of thermal expansion (α, given as 1.4×10-5/°C) multiplied by the increase in temperature (ΔT) and the length of the member (L). This assumes a uniform temperature (i.e. no gradient between top and bottom flanges of the beam) and “no restraint to thermal expansion” (emphasis added; i.e., no shear studs on the beam). So, for a long span beam in the northeast corner (601.75 inches ), assuming a temperature of 600 °C:

δT = α ΔT L = (1.4×10-5/°C) x (600°C) x (601.75 in.) = 5.05 in.

Thus, even given the above assumptions, according to NIST’s own mathematical formula for a worst-case hypothetical scenario, a beam connected to the critical girder would elongate by 5.05 inches. Interestingly, in its own example, NIST does not perform this calculation for one of the long span beams in the northeast corner, but for a girder of shorter length. This is odd since the entire question here, for NIST’s purposes, is with regard to its hypothesis that floor beams pushed the critical girder connected to Column 79 off its seat. The explanation may be implicit in the fact that NIST states elsewhere in its final report that the travel distance of the girder to walk off its seat laterally was 5.5. inches. For a beam to elongate 5.5 inches, even according to the above worst-case scenario, it would have to achieve a uniform temperature of about 653°C, which seems highly unlikely if not impossible for a fire-insulated beam heated for just 20-30 minutes by fires (real-world, as opposed to simulated). NIST’s own computer model assumed a maximum temperature of 500°C for the girder and 600°C for the beams in a worst-case scenario designed to set “boundary conditions and temperatures … to create maximum shear forces” (emphasis added).

So, yes, NIST has not even a starting point. Their hypothesis is absolute scientific fraud from top to bottom.
- Sean
  
  February 28, 2011 at 3:48 am
  
  The Nist report says the girder was knocked off of it’s support and needed 5.05 inches to do so; as your math explains the beam would lengthin at worst case 5.05inches and the seat needs this 5.05 inches to move in order to fall off….well the beam girder could only move 2.5 inches because the opposite girder would have similiar movement as well somewhere around half and half. Also the steel is very ductile even the bolts will stretch to an incredible distance before they fail……I don’t know what the connection looks like but any typical connection known to me would have to stretch and yield at least 12 -20 inches before it fails….if someone duplicates this scenario I can bet the connection will only deform but will be know where near failure….after the girder falls off in the NIST report the column fails….again it’s too strong to fail even when the lateral support is removed….this is my common sense speaking, as I do not know what these members are so I cannot provide proof. Again it’s impossible to heat the beam to that degree in the first place so I don’t understand how they can get away with this, every engineer on that report should have their licences pulled. 20 to 30 minutes of fire could only blacken the paint.
  - Jeremy R. Hammond
    
    February 28, 2011 at 4:28 am
    
    Also, the girder could not have been pushed off its seat because although Column 79 is a box column, it did have flanges that stuck out, which the girder was between. In fact, the NIST report even STATES that in their model, the girder was pushed until it was restricted by this flange, and they show a picture of it.
    
    Scientific fraud. Outright.
    - Sean
      
      February 28, 2011 at 5:58 am
      
      I have severe chest pains right now from reading the hog wash in the NIST report. It’s very disturbing from my perspective and does not make sense to me….I went back to look for the connection you said would be in the NIST report and I cannot find a detail of the connection. However, I looked at the girders framing into column 79 and all three columns laterally support the column….if you remove one you have lateral support in both axis of the column from the other two girders so to say it buckled from no lateral support from only one girder being knocked off it’s connection is false, this I can prove without a doubt that column 79 had lateral support;….just by inspection of the framework of the floor, the beams and girders at that column, so how can they justify no lateral support….am I missing something here;… because even if you remove two girders you still have lateral support to column 79 from one girder….any one girder will give lateral support to that column in both axis…..why?… because of the triangular formation of the floor beams and girders that come to column 79 Any one girder connected to column 79 provides support by means of pull (tension) or push (compression) however it can still provide connection support in the sideway sway because in order to move any one girder sideways you would have to move all the other beams with it that connect to that girder which all connect to another opposite girder which connect to columns for support….in that I am saying the entire floor at column 79 is a diaghram not only by means of the concrete floor slab but by means of all the structural steel as well… this column is alone but is specifically special because it has lateral support framing into it three ways from three different girders….therefore I am saying without a doubt that if so much as one of those three girders remained attached to that column then column 79 was laterally supported…again to my discust that I need even go here because even without lateral support this column would not fail under only dead loads even without lateral support.
    - Jeremy R. Hammond
      
      February 28, 2011 at 6:31 am
      
      Look to NCSTAR 1-9 Vol 1, p. 353. Also from my yet-to-be-published paper on WTC 7:
      
      Even given all of the above assumptions (i.e. uniform temperature throughout member, failure of shear studs on beams, no shear studs on girder, 500-600°C structural temperatures), NIST’s own computer model showed that “axial expansion of the floor beams pushed the girder laterally, where it came to bear against the inside of the column flange.” That is to say, the flange of Column 79 restricted any further westward movement of the girder (Figure 27).
      
      On lateral support for 79, I don’t think NIST really summarized the extent of the loss very well, but you can look at their damage assessment input data for each floor and see that there was still lateral support on some floors, particularly the girders west and south of 79. They argue the greater loss of support north and east caused it to buckle in that direction. I don’t have the engineering knowledge to be able to challenge that, but it’s something I question, also, since that would mean the intact girders connected to column 79 would offer restraint to outward bowing.
    - Sean
      
      February 28, 2011 at 4:23 pm
      
      The girder connections are designed to hold the floor up and are very strong as compared to what is needed to stop the girder from bowing, it’s a negligible load condition that I have never had to design for…all the girder does is keep the column straight with regards to their relationship with a minimal load to hold it straight, and yes if the column did bow then the other two girders have to come along for the ride pulling everything with it even collapsing the outer columns that are designed to withstand hurricane forces….this is impossible to say the least…if this was true then it should have buckled the building when they were all attached…same thing…basically….again for column 79 to buckle in the North – East direction, it has to take the other two girders with it, if they were attached then NIST is falsifying the claim that column 79 buckled due to know support from one girder being detached. Again like you said it can’t be pushed off of it’s seat to begin with if it was between two plates and due to the fact steel connections will yield a lot more than 5 inches before failure ever occurs.
    - Sean
      
      February 28, 2011 at 5:06 pm
      
      Correction to the previous sentence in capitization
      
      The girder connections are designed to hold the floor up and are very strong as compared to what is needed to STOP COLUMN 79 from bowing

Jeffrey Orling RA

February 27, 2011 at 2:48 pm

Sean,
One can do some reverse engineering to size the steel. Even if it is conservative or over sized it is possible to get a pretty close approximation to the size and types of connections used for the structure… and even more so having images from the construction phase in some cases. So like any structure design you being with the live load, the areas, the dead loads and so forth. Yes you do have to consider wind shear and the special loads like HVAC equipment, tanks and so forth.

But these loads have little to do with the floor loads, and the beams which support them. I am not an engineer and I don’t know how wind shear would be taken into consideration as additional steel. My understanding is that it is mostly to make the frame stiffer and typically would involve diagonal members or if no possible a more rigid and heavier core.

But I do believe in the WTC collapses they all were involving not column failure exclusively, but floor systems failures which LED to column buckling. The composite floors acted as bracing for the columns and if that bracing was removed first the columns load carrying capacity drops and if this extends over enough floors the columns WILL buckle and pop out of axial alignment. This leads to a progression of failures in the core columns until there is not enough to carry the central loads, the unsupported mass drops with no resistance, guts the remaining central area, pulls in the perimeter and the building folds in on itself.

I think this IS a plausible scenario which matches the observations. The problem then becomes how does one achieve multiple local floor collapses to destroy the bracing of core column(s) in such a manner that one or more columns stripped of their bracing will lead to a progressive failure of all the core columns? This, I think is what happened in 7, but not what happened in 1 & 2.

The NIST FEA is an attempt to track a progressive failure from a fire related heat expansion and a key girder (bracing) dropping off a single seat. Not only does it not look like the failure we say, but it stretches credulity. The tried the same slight of hand heat expansion in the twins and that too was bogus.

I think the more plausible cause was an attack on multiple floors at the same column(s) which is hardly likely from office fires. They clearly don’t want to look at something OTHER than office fires because that undermines their hijacked planes caused fires and fires can weaken steel and make building collapse.

But the fact remains, in my opinion, that all these long span column free tenant spaces in high rises are susceptible to progressive floor collapses if enough of the floors can collapse locally. The twin towers with the rather flimsy trusses was an example of this “poor design” or vulnerable design concept on steroids. And so the strength of the columns had little to do with preventing the collapse.

And this brings me to the “arguments” to persuade the public. It is true that the technical argument is outside the understanding of not only the general public but even many scientists who are not familiar with structural design. And so the arguments seem to have devolved to cartoon like simplistic presentations which in fact are not really true.. Such as the Gage list of signs of controlled demolition and the logic if it looks like a duck, quacks like a duck and walks like a duck it HAS to BE a duck. Perhaps this is a good point to examine the real evidence, but such arguments are not conclusive.

It’s like finding a person dead with what looks like a bullet wound. The forensic examiner must not only determine that the bullet wound was fatal, but find the bullet, link it to a specific gun and then somehow determine who fired that shot with that gun.

We’re really very early on in the forensic case… we have the dead body (collapsed buildings). Now we need to know what caused it to die (collapse). And there are some that say it didn’t even collapse .. it came down too fast for a collapse.

So in the interest of truth, since an investigation will lead to the perps, we do need to properly understand what happened.

I for one don’t think the truth movement is doing a good job of this and in some cases appears to not be concerned with it. The gov lied, the gov is complicit. Case closed. So we convict them of perjury… the what?

Jeremy R. Hammond

February 27, 2011 at 3:56 pm

To properly understand what happened, we need to explain free-fall. Your hypothetical does not and cannot explain gravitational acceleration for 2.25 seconds, as I’ve elaborated on in more detail previously.
- Jeffrey Orling RA
  
  February 27, 2011 at 5:10 pm
  
  It most certainly DOES.
  
  Once the core was gutted by the top plunging down through the center of the building, the remaining columns buckled removing any axially support in the core side of the floors which yanked at the perimeter columns pulling them off axis and the whole mass dropped until some of the columns in the remaining descending structure crashed into the resistance of material below which was not destroyed and still connected to the foundations.
  - Jeremy R. Hammond
    
    February 28, 2011 at 3:13 am
    
    But that’s what I mean. Your scenario requires that columns be buckling, just as NIST’s does. In fact, it rather seems to be the same argument NIST makes. But, like NIST, you’re neglecting free-fall. There was no energy available to buckle columns. Which means some other force must have acted upon them causing their structural integrity to be reduced to 0 near instantaneously for all perimeter columns.
    
    Your scenario cannot account for that. Only the CD hypothesis accounts for all the evidence. Your scenario also seems not to take into account the presence of thermitic materials and iron-rich microspheres in the dust, among other evidence.